1. Field of the Invention
This invention relates to a radio communication apparatus, and more specifically to a radio communication apparatus and a method for radio communication for use in case of an emergency.
2. Description of the Related Art
Users of a radio communication apparatus have a duty when an emergency such as disaster occurs, the users have to inform many other radio users of stricken conditions by radio.
In case of amateur radio communication apparatus, it is the general use when an emergency occurs, the user changes the operating frequency to a predetermined CALL frequency before communication. For example, in an FM communication, JARL (Japan Amateur Radio League) designates a CALL frequency for an emergency communication frequency, 433 MHz for a main frequency, 433.50 MHz for a sub frequency, etc. When the CALL frequency is set for an emergency communication frequency, someone who is waiting for a call can receive an emergency communication, and can be informed of occurrence of emergency and these conditions.
However, when an emergency occurs, a conventional radio communication apparatus has to be changed from a communicating frequency to an emergency communication frequency by the operator him/herself. Therefore, prompt correspondence can not be done.
And when a reception side radio communication apparatus receives a radio which indicates occurrence of emergency, if the sound volume of the reception side radio communication apparatus is low, the operator can not be informed of received contents. The same matter occurs, for example, in the case of the system which is composed of a base station and a plurality of branch stations, when a base station calls branch stations.
Moreover, a conventional radio communication apparatus can not be used when an owner is in a disaster and can not operate for radio communication, the owner can not ask for help by using a radio communication apparatus.
The present invention has been made in consideration of the above-described conditions, and it is an object of the present invention to provide a radio communication apparatus and a method for radio communication which can be used effectively when an emergency occurs.
It is a further object of the present invention to provide a radio communication apparatus and a method for radio communication which can promptly change an operating frequency to an emergency communication frequency by easy operation.
It is a still further object of the present invention to provide a radio communication apparatus and a method for radio communication which can automatically adjust the sound volume on appropriate value in response to a call.
It is another object of the present invention to provide a radio communication apparatus when an owner him/herself is in a disaster, the owner can ask for help by using it.
According to the first aspect of the present invention having the above-described objects, there is provided a radio communication apparatus comprised of a switch, a speaker, a speaker driver for driving the speaker and emitting a warning sound in response to an operation of the switch, and a transmitter for transmitting a predetermined warning signal by radio in response to an operation of the switch.
According to this structure, when an emergency occurs to an owner of this radio communication apparatus, by only depressing a switch (button, key, etc.) can be informed of an emergency of people a short-distance away by an alarm sound from a speaker, and of people a long-distance away by radio. Therefore, the owner of this radio communication apparatus can be easily rescued.
The speaker driver outputs a burst signal in response to the operation of the switch. The speaker is also operated by this burst signal. In this case, the transmitter can also transmits the burst signal by radio in response to the operation of the switch.
The transmitter can also change from the current frequency to a predetermined frequency in response to the operation of the switch.
Irrespective of speaker volume, it can also emit an alarm sound from the speaker on predetermined sound volume.
According to the second aspect of the present invention having the above objects, there is provided a radio communication apparatus comprised of:
a receiver for receiving a radio signal;
a speaker for emitting a sound signal contained in a radio signal received by the receiver;
a volume switch for adjusting sound volume of the speaker;
discrimination means for discriminating whether or not a radio signal received by the receiver contains a predetermined control signal; and
means for adjusting sound volume of the speaker to a predetermined level irrespective of the sound volume when the discrimination means discriminates that the radio signal contains the predetermined control signal.
The radio communication apparatus containing that structure sets the volume of a speaker to a predetermined level such as the maximum level when a predetermined control signal is received irrespective of the volume setting of the speaker. Therefore, it can prevent from the case, for example, in which an owner of the radio communication apparatus fails to hear a received sound because sound volume is too low, and it can diminish miss hearing. Thus, it is superior in emergency communication.
The predetermined control signal contains, for example, a discrimination code allotted from a received signal of the receiver to itself and a predetermined emergency control code.
The predetermined control signal is a control code based on one code system of such as CTCSS (Continuous Tone Controlled Squelch System), MSK (Minimum Shift Keying), DCS (Digital Coded Squelch), DTMF (Dual Tone Multi Frequency), 2TONE (Two Tone Signaling) and 5TONE (Sequential Tone Signaling).
The above radio communication apparatus may further be comprised of a switch for indicating emergency, and a function for transmitting a discrimination code allotted to itself and a discrimination code indicating emergency in response to the operation of the switch.
According to the third aspect of the present invention having the above objects, there is provided a radio communication apparatus, wherein:
a switch;
a transmitter for transmitting a predetermined code one time with a first frequency in response to the operation of the switch when the switch is operated while communicating with another radio communication apparatus with the first frequency, and then transmitting the predetermined code with a second frequency which is different from the first frequency; and
a receiver for changing the reception frequency to the second frequency when a predetermined code is received while communicating with the another radio communication apparatus using the first frequency.
According to the radio communication apparatus of this structure, a communication frequency can be immediately changed to the second frequency by operating a switch during communication. Normally, in case of emergency communication (urgent communication), it is allotted to an emergency communication frequency which is different from a normal communication frequency. Therefore, the first frequency is set for normal communication and the second frequency is set for emergency communication, and both reception and transmission sides can immediately change to an emergency communication frequency when an emergency occurs in communication.
According to the fourth aspect of the present invention having the above objects, there is provided a radio communication apparatus, wherein:
an emergency switch for indicating occurrence of emergency;
memory for storing a control code indicating occurrence of emergency;
transmission means for reading out the control code from the memory by an operation of the emergency switch, and transmitting the control code with the former transmission frequency;
means for changing the transmission frequency of the transmission to an emergency communication frequency after transmission of the control code; and
reception means for receiving a radio signal and changing the call frequency upon detection of the control code in the received signal.
This structure also enables that both reception and transmission sides can immediately change to an emergency communication frequency when an emergency occurs in communication.
The above radio communication apparatus may comprise means for returning to the former frequency after measuring the suspension period of time of communication of an emergency communication frequency and when the suspension period of time exceeds a predetermined period.
The above radio communication apparatus may also comprise the transmission means transmits a signal containing a discrimination code allotted to itself in response to the operation of the emergency switch on an emergency communication frequency and the reception means discriminates whether or not the suspension period of a received signal with a discrimination code of a remote radio station is exceeded, and when it is determined that the suspension period exceeds a fixed period, return to the former call frequency.
The control code is a control code based on one code system of such as CTCSS, MSK, DCS, DTMF, 2TONE and 5TONE.
According to the fifth aspect of the present invention having the above-described objects, there is provided an emergency alerting method using a radio communication apparatus, the method comprises the steps of emitting an alarm sound from a speaker in response to an operation of a switch indicating occurrence of emergency and transmitting a predetermined alarm signal by radio in response to the operation of the switch.
According to the sixth aspect of the present invention having the above-described objects, there is provided a sound volume control method comprising:
a reception step of receiving and reproducing a radio signal and emitting a sound;
an adjusting step of adjusting a volume of a sound emitted by the reception step;
a discrimination step of discriminating whether or not a received radio signal contains a predetermined control signal; and
a setting step of setting the volume of the sound to a predetermined level irrespective of the volume adjusted by the adjusting step when the received signal discriminated by the discrimination step contains the predetermined control signal.
According to the seventh aspect of the present invention having the objects described above, there is a method provided for changing a communication frequency in case of emergency while at least two radio communication apparatuses, including first and second radio communication apparatuses, are communicating with each other using a first communication frequency and when a predetermined switch with which the first radio communication apparatus is equipped is operated, the method comprising steps of:
transmitting a predetermined code one time with the first frequency from the first radio communication apparatus, and then transmitting a predetermined code with a second frequency for emergency communication from the first radio communication apparatus receives a predetermined code transmitted from the first radio communication apparatus; and
making the second radio communication apparatus change a reception frequency to the second frequency when the second radio communication apparatus receives the predetermined code transmitted with the first frequency from the first radio communication apparatus.